High-torque power wrenches, such as are described, for example, in U.S. Pat. No. 3,706,244, are now widely used on flanged connections. Each full swing of the power wrench is usually limited to an angular excursion ranging between 30.degree. and 70.degree.. A well-recognized drawback of such power wrenches is that, after each full swing, the wrench must be lifted from the threaded connector on the flanged connection and manually repositioned.
Ratchet wrenches for loosening or tightening nuts and bolts are well known, but they do not lend themselves for applications such as are described in said U.S. Pat. No. 3,706,244, because the torque applied to the housing of a conventional ratchet wrench produces both a substantial bending moment and a tensile force in the housing, which must be made sufficiently large and heavy to maintain its structural integrity.
But, the spacings between adjacent bolts on typical flanged connections, secured by high-torque bolts, are such that a large wrench housing would not fit in the available inter-bolt spacings. If the ratchet housing were to be elevated above the plane of the nuts or bolts, then it would become additionally subjected to eccentric loads, requiring the ratchet housing to be even larger in size and heavier.
It is a main object of the present invention to overcome the above mentioned and other well-known drawbacks of conventional ratchet wrenches, and to provide a new and improved high-torque ratchet wrench which can be made sufficiently small so that it can be used on flanged connections with closely spaced bolts.